CN114502693A

CN114502693A - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: CN114502693A
Application number: CN202080066914.1A
Authority: CN
Inventors: 大野慎跃; 须贺贵裕; 山本雄介
Original assignee: Nissan Chemical Corp
Current assignee: Nissan Chemical Corp
Priority date: 2019-09-24
Filing date: 2020-09-23
Publication date: 2022-05-13
Also published as: TW202140619A; JPWO2021060270A1; WO2021060270A1; KR20220066246A

Abstract

The invention provides a liquid crystal aligning agent for forming a liquid crystal aligning film which has high refractive index and high light transmittance because of no coloring property, a liquid crystal aligning film obtained by the liquid crystal aligning agent, and a liquid crystal display element with the liquid crystal aligning film. A liquid crystal aligning agent characterized by containing the following components (A) and (B). (A) The components: at least one polymer (A) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (a) and a polyimide which is an imide compound of the polyimide precursor, and a process for producing the sameThe diamine (a) has at least one selected from the group consisting of structures represented by the following formulae (S1) to (S3). (B) The components: at least one polymer (B) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (B) represented by the following formula (2) and a polyimide which is an imide compound of the polyimide precursor. (X)¹，X²Represents a single bond, - (CH)₂)_a- (a is an integer of 1 to 15), and the like. G¹And G²A divalent aromatic group having 6 to 12 carbon atoms. m and n are 0 to 3. R¹Represents an alkyl group having 1 to 20 carbon atoms or the like. ) (X)³Represents a single bond, -CONH-, or the like. R is²Represents an alkyl group having 1 to 20 carbon atoms or the like. ) (X)⁴represents-CONH-, -NHCO-, or the like. R³Represents a structure having a steroid skeleton. ) (A)₁、A₂Represents a divalent monocyclic or condensed ring group, A₁And A₂At least one of (a) represents a divalent condensed ring group. L represents a single bond or a divalent organic group. m and n are 1-3. )

‑X³‑R²(S2)‑X⁴‑R³(S3)

Description

Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element

Technical Field

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display element provided with the liquid crystal alignment film.

Background

Conventionally, various driving methods have been developed for liquid crystal display elements, which are different In electrode structure, physical properties of liquid crystal molecules used, and the like, and various display elements such as TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, VA (Vertical Alignment) type, IPS (In-Plane Switching) type, and FFS (Fringe Field Switching) type are known.

The liquid crystal display element is generally configured as follows: a pair of electrode substrates are arranged to face each other with a predetermined gap (several μm), and liquid crystal is sealed between the electrode substrates. Then, a voltage is applied between the transparent conductive films of the electrodes constituting the electrode substrate, whereby display is performed in the liquid crystal display element. These liquid crystal display elements also have a liquid crystal alignment film for aligning liquid crystal molecules. As a material of the liquid crystal alignment film, for example, polyamic acid ester, polyimide, polyamide, and the like are known (see patent document 1 and the like).

Documents of the prior art

Patent document

Patent document 1: international publication No. 2016/080458

Disclosure of Invention

Problems to be solved by the invention

The transparent conductive film in the liquid crystal display device is usually formed of a composition (ITO) containing indium oxide as a main component and tin oxide doped thereto by a few%, but the refractive index thereof is different from that of the liquid crystal alignment film and has a high value. Therefore, when light from the display light source is transmitted through the electrode substrates, the light is reflected at the boundary surface between the transparent conductive film and the liquid crystal alignment film in each electrode substrate. As a result, the light transmittance of the electrode substrate cannot be sufficiently obtained, which causes a problem of lowering the display luminance.

In particular, in recent years, ultra-fine panels such as 4K and 8K panels have been developed, but in these panels, the occupancy of Black Matrix (BM) and TFT has been increased, the aperture ratio of the panel has been decreased, and the improvement of the transmittance of the display portion has been regarded as important.

Therefore, the present inventors have made various studies on materials for forming the liquid crystal alignment film in order to increase the refractive index of the liquid crystal alignment film, from the viewpoint that the above-described problems can be solved by reducing the difference between the refractive index of the transparent conductive film and the refractive index of the liquid crystal alignment film. Specifically, in order to increase the refractive index of the liquid crystal alignment film, the types of polymers contained in various liquid crystal alignment agents for forming the liquid crystal alignment film have been investigated.

As a result, it was found that a liquid crystal alignment film having a high refractive index similar to the refractive index of the transparent conductive film can be obtained by selecting a specific polymer, but on the other hand, when the number of polymers forming the liquid crystal alignment film having a high refractive index is large, the liquid crystal alignment film has coloring property. In such a case, the liquid crystal alignment film formed from a liquid crystal aligning agent containing a polymer having coloring property has a low light transmittance, resulting in a low display luminance, and as a result, the above object cannot be achieved.

In view of the above, an object of the present invention is to provide a liquid crystal aligning agent for forming a liquid crystal alignment film having a high refractive index and a high light transmittance because of no coloring property, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display element having the liquid crystal alignment film.

Means for solving the problems

The present inventors have conducted intensive studies to achieve the above-mentioned problems, and as a result, have found that a liquid crystal aligning agent comprising a part of a novel polymer and two or more polymers having specific structures is effective for achieving the above-mentioned objects, and have completed the present invention.

The present invention provides a liquid crystal aligning agent, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display element having the liquid crystal alignment film, wherein the liquid crystal aligning agent contains the following component (A) and component (B).

(A) The components: at least one polymer (A) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (a) having at least one selected from the group consisting of structures represented by the following formulae (S1) to (S3), and a polyimide which is an imide product of the polyimide precursor.

(B) The components: at least one polymer (B) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (B) represented by the following formula (2) and a polyimide which is an imide compound of the polyimide precursor.

(X¹And X²Each independently represents a single bond, - (CH)₂)_a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH)₃)－、－NH－、－O－、－COO－、－OCO-or- ((CH₂)_a1－A₁)_m1- (a1 is an integer of 1 to 15, A)₁Represents an oxygen atom or-COO-, m₁Is an integer of 1 to 2. At m₁In the case of 2, a plurality of a1 and A₁Each independently having the definition). G¹And G²Each independently represents a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms or a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group is optionally substituted by an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms or a fluorine atom. m and n are respectively and independently integers of 0-3, and m + n is 1-6, preferably 1-4. R¹Represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms to form R¹Optionally substituted with fluorine atoms. )

x³-R²(s2)

(X³Represents a single bond, -CONH-, -NHCO-, -CON (CH)₃)－、－NH－、－O－、－CH₂O-, -COO-or-OCO-. R²Represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms to form R²Optionally substituted with fluorine atoms. )

x⁴-R³(S3)

(X⁴represents-CONH-, -NHCO-, -O-, -CH₂O－、－OCH₂-, -COO-or-OCO-. R³Represents a structure having a steroid skeleton. )

(A₁And A₂Each independently represents a divalent monocyclic group or condensed ring group optionally having a substituent, A₁And A₂At least one of (a) represents a divalent condensed ring group optionally having a substituent. L represents a single bond, -COO-),-CO-S-, -CO-, -CONR- (wherein R is a hydrogen atom or a monovalent alkyl group having 1 to 6 carbon atoms), -O-, -S-or a divalent organic group. m and n are each independently integers of 1 to 3. )

Effects of the invention

According to the present invention, a liquid crystal aligning agent capable of forming a liquid crystal alignment film having a high refractive index and a high light transmittance because of no coloration can be obtained. The liquid crystal alignment film formed by the liquid crystal alignment agent can reduce the difference between the refractive index of the transparent conductive film and the refractive index of the liquid crystal alignment film in the liquid crystal display element, and has no coloring property, so that the liquid crystal display element with high light transmittance and high display brightness can be obtained.

Detailed Description

The liquid crystal aligning agent of the present invention is characterized by containing the following component (A) and component (B) as described above.

(component A: Polymer (A))

The component (a) in the present invention is at least one polymer (a) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (a) having at least one selected from the group consisting of structures represented by the following formulae (S1) to (S3), and a polyimide which is an imide product of the polyimide precursor.

Formula [ S1]X in (1)¹、X²、G¹、G²、R¹M, n are as defined above.

In addition, G is defined as¹、G²The divalent cyclic group in (1) includes, for example: cyclopropyl, cyclohexyl, phenylene. Any hydrogen atom in the cyclic groups is optionally substituted by an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms or a fluorine atom.

X³-R²[s21

Formula [ S2]In, X³、R²Is as defined above. In view of improving the liquid crystal alignment property, R is²Preferably an alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms.

X⁴-R³[s31

Formula [ S3]In, X⁴、R³Is as defined above. Furthermore, R³Structures comprising cholestanyl, cholesteryl or lanostanyl groups are preferred.

Preferable examples of the formula [ S1] include the following formulae [ S1-x 1] to [ S1-x 7 ].

In the above formula, R¹Is an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. X^pIs- (CH)₂)_a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH)₃)－、－NH－、－O－、－CH₂O－、－CH₂OCO-, -COO-, or-OCO-. A. the₁Is oxygen atom or-COO- (-wherein, the bond with "+") and (CH)₂)_a2Bonding) A₂Is oxygen atom or-COO- (wherein, the bonding bond with₂)_a2Bonding) a₃Is 0 or 1, a₁And a₂Each independently an integer of 1 to 10, Cy is 1, 4-cyclohexylene or 1, 4-phenylene

As formula [ S2]Preferred embodiment of (1), X³is-O-, -CH₂Any of O-, -COO-or-OCO-, preferably R²When the alkyl group has 3 to 20 carbon atoms or the alkoxyalkyl group has 2 to 20 carbon atoms, R is more preferably²In the case of an alkyl group having 3 to 20 carbon atoms, R is formed²Optionally substituted with fluorine atoms.

Preferred examples of the formula [ S3] include the following formula [ S3-x ]. In the formula [ S3-X ], X is a formula [ X1], a formula [ X2] or [ X3], Col is a formula [ Col1], a formula [ Col2] or a formula [ Col3], G is a formula [ G1], a formula [ G2], a formula [ G3] or a formula [ G4 ]. Me represents a methyl group.

The diamine (a) having the structure represented by the above formulae (S1) to (S3) is preferably a diamine represented by the following formula [1] or formula [2 ].

The above formula [1]、[2]Wherein Y represents the above formula [ S1]～[S3]The side chain structure shown is formula [2]Optionally the two Y's in (a) are the same or different. X represents a single bond, -O-, -C (CH)₃)₂－、－NH－、－CO－、－(CH₂)_m－、－SO₂－、－O－(CH₂)_m－O－、－O－C(CH₃)₂－、－CO－(CH₂)_m－、－NH－(CH₂)_m－、－SO₂－(CH₂)_m－、－CONH－(CH₂)_m－、－CONH－(CH₂)_m－NHCO－、－COO－(CH₂)_m－OCO－、－COO－、－CONH－、－NH－(CH₂)_m-NH-or-SO₂－(CH₂)_m－SO₂-. m is an integer of 1 to 8.

Preferred examples of the diamine represented by the above formula [1] include the following formulae [ S-1 ] to [ S-18 ].

(n is an integer of 1 to 20.)

Preferable examples of the diamine represented by the above formula [2] include those selected from the group consisting of the following formulas [ W-1 ] to [ W-6 ].

In the above formula, X^p1～X^p8Independently of each other of the formula [ S1-x 1]]～[S1－x6]X of (2)^pSynonymously. X^s1～X^s4Each independently represents-O-, -CH₂O－、－OCH₂-, -COO-or-OCO-. X_a～X_frepresents-O-, -NH-, -O- (CH)₂)_m－O－、－C(CH₃)₂－、－CO－、－COO－、－CONH－、－(CH₂)_m－、－SO₂－、－O－C(CH₃)₂－、－CO－(CH₂)_m－、－NH－(CH₂)_m－、－NH－(CH₂)_m－NH－、－SO₂－(CH₂)_m－、－SO₂－(CH₂)_m－SO₂－、－CONH－(CH₂)_m－、－CONH－(CH₂)_m-NHCO-, or-COO- (CH)₂)_m－OCO－，R^1a～R^1hEach independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. m is an integer of 1 to 8.

(component B: Polymer (B))

The component (B) in the present invention is at least one polymer (B) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a part of the novel diamine (B) represented by the following formula (2) and a polyimide which is an imide compound of the polyimide precursor.

In the above formula (2), A₁、A₂L, m and n are as defined above.

A₁、A₂The monocyclic group in (1) is a divalent group obtained by removing two hydrogen atoms from a single ring. Examples of monocyclic rings include: benzene; five-membered heterocycles such as furan, thiophene, pyrrole, oxazole, thiazole, imidazole and pyrazole; six-membered heterocyclic rings such as pyran, pyrone, pyridine, pyridazine, pyrimidine, pyrazine, and the like. Monocyclic rings are preferably benzene or pyridine. When the monocyclic ring is benzene, the monocyclic group is phenylene.

A₁、A₂The condensed ring group in (3) is a divalent group obtained by removing two hydrogen atoms from a condensed ring. Examples of the condensation ring include: condensed polycyclic aromatic hydrocarbons such as naphthalene, tetralin, indene, fluorene, anthracene, phenanthrene, and pyrene; condensed polycyclic heterocycles such as benzofuran, benzothiophene, indole, carbazole, coumarin, benzopyrone, quinoline, isoquinoline, acridine, phthalazine, quinazoline, quinoxaline, and the like. The condensed ring is preferably any of naphthalene, anthracene, pyrene, indole, carbazole, coumarin, benzopyrone, quinoline, or isoquinoline.

A₁、A₂The monocyclic group and the condensed ring group in (1) may have a substituent. Examples of the substituent in the monocyclic group and the condensed ring group include: an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, etc.

Examples of the divalent organic group in L include: a divalent chain hydrocarbon group having 1 to 20 carbon atoms; a group in which at least one methylene group of the chain hydrocarbon group is substituted with-COO-, -COS-, -CO-, -CONR- (wherein R represents a hydrogen atom or a monovalent alkyl group having 1 to 6 carbon atoms), -O-, -S-, or the like. The chain hydrocarbon group may be branched or linear, and may be saturated or unsaturated. The divalent chain hydrocarbon group having 1 to 20 carbon atoms includes an alkylene group having 1 to 20 carbon atoms. From the viewpoint of compatibility between a high refractive index and a high light transmittanceL is preferably a single bond, - (CH)₂)_n- (n is 1 to 20, more preferably 1 to 10, further preferably an integer of 1 to 6), -O- (CH)₂)_n-O- (n is 1 to 20, more preferably 1 to 10, further preferably an integer of 1 to 6), -O- (CH)₂)_n- (n is 1 to 20, more preferably 1 to 10, further preferably an integer of 1 to 6), -S- (CH)₂)_n-S- (n is 1 to 20, more preferably 1 to 10, and still more preferably an integer of 1 to 6), or-S- (CH)₂)_n- (n is 1 to 20, preferably 1 to 10, and more preferably an integer of 1 to 6). And A in the above formula (2)₁、A₂The relevant m and n are preferably 1 or 2.

Among them, the diamine (b) is preferably a diamine represented by the following formulae (2-1) to (2-25).

(production of Polymer (A) and Polymer (B))

The polymer (a) and the polymer (B) contained in the liquid crystal aligning agent of the present invention are each a polyimide (a) and a polyimide (B) obtained using a diamine component containing the diamine (a), a polyimide precursor (a) and a polyimide precursor (B) obtained using a diamine component containing the diamine (B), or an imide compound which is the polyimide precursor. Here, the polyimide precursor is a polymer which can give polyimide by imidization of polyamic acid, polyamic acid ester, or the like.

The polyamic acid (a) which is a polyimide precursor of the polymer (a) can be obtained by a polymerization reaction of a diamine component containing the diamine (a) and a tetracarboxylic acid component.

In this case, the amount of the diamine (a) used is preferably 1 mol% or more, more preferably 5 mol% or more, based on the diamine component reacted with the tetracarboxylic acid component. When a diamine other than the diamine (a) is used in combination, the amount of the diamine (a) used is preferably 99 mol% or less, and more preferably 95 mol% or less.

The polyamic acid (B) which is a polyimide precursor of the polymer (B) can be obtained by a polymerization reaction of a diamine component containing the diamine (B) and a tetracarboxylic acid component.

In this case, the amount of the diamine (b) to be used is preferably 1 mol% or more, more preferably 2 mol% or more, based on the diamine component to be reacted with the tetracarboxylic acid component. When a diamine other than the diamine (b) is used in combination, the amount of the diamine (b) used is preferably 99 mol% or less, and more preferably 95 mol% or less.

The diamine component used for the production of the polyamic acids (a) and (B) may contain a diamine other than the diamine (a) and a diamine other than the diamine (B) (hereinafter, also referred to as another diamine). Examples of other diamines are given below, but the present invention is not limited thereto.

Diamines having a carboxyl group such as p-phenylenediamine, m-phenylenediamine, 4- (2- (methylamino) ethyl) aniline, 3, 5-diaminobenzoic acid, 4 ' -diaminodiphenylmethane, 3 ' -diaminodiphenylmethane, 4 ' -diaminodiphenyl ether, 3 ' -diaminodiphenyl ether, 4 ' -diaminobenzophenone, 3 ' -diaminobenzophenone, 1, 2-bis (4-aminophenyl) ethane, 1, 3-bis (4-aminophenyl) propane, 1, 4-bis (4-aminophenyl) butane, 1, 4-bis (4-aminophenoxy) benzene, 1, 3-bis (4-aminophenoxy) benzene, 1, 2-bis (4-aminophenoxy) ethane, 1, 2-bis (4-amino-2-methylphenoxy) ethane, 1, 3-bis (4-aminophenoxy) propane, p-phenylenediamine, m-phenylenediamine, 4- (2- (methylamino) ethyl) aniline, 3, 5-diaminobenzoic acid, etc., 1, 4 ' -diaminobenzophenone, 1, 2-bis (4-aminophenoxy) ethane, 1, 3-bis (4-aminophenoxy) propane, 3-bis (4-phenoxy) propane, 3-aminobenzoic acid, etc, 1, 4-bis (4-aminophenoxy) butane, 1, 5-bis (4-aminophenoxy) pentane, 1, 6-bis (4-aminophenoxy) hexane, 4- (2- (4-aminophenoxy) ethoxy) -3-fluoroaniline, bis (2- (4-aminophenoxy) ethyl) ether, 4-amino-4 '- (2- (4-aminophenoxy) ethoxy) biphenyl, 2' -dimethyl-4, 4 '-diaminobiphenyl, 3' -dimethyl-4, 4 '-diaminobiphenyl, 1, 4-diaminonaphthalene, 1, 5-diaminonaphthalene, 2, 6-diaminonaphthalene, 2, 7-diaminonaphthalene, 2' -bis [ 4- (4-aminophenoxy) phenyl ] propane, 2 '-bis [ 4- (4-aminophenoxy) phenyl ] hexafluoropropane, 2' -bis (4-aminophenyl) propane, Diamines having a urea bond such as 1, 3-bis (4-aminophenylethyl) urea, diamines having a photopolymerizable group at the terminal such as 2- (2, 4-diaminophenoxy) ethyl methacrylate and 2, 4-diamino-N, N-diallylaniline, diamines having a radical-initiating function such as the following formulae (a-1) to (a-6), diamines having a radical-initiating function such as the following formulae (R1) to (R5), diamines having a heterocyclic ring such as the following formulae (z-1) to (z-18), diamines having a diphenylamine skeleton such as the following formulae (Dp-1) to (Dp-3), diamines having an oxazoline structure such as the following formulae (Ox-1) to (Ox-2), and the like, An organosiloxane-containing diamine such as 1, 3-bis (3-aminopropyl) -tetramethyldisiloxane, a diamine described in International publication No. 2016/125870, and the like.

(d1 represents an integer of 2 to 10.)

(n represents an integer of 2 to 10.)

In order to improve the response speed of a liquid crystal display device using a PSA (Polymer stabilized Alignment) system or an SC-PVA (Patterned Vertical Alignment) mode, one or more of the 4, 4 '-diaminobenzophenone, 3' -diaminobenzophenone, a diamine having a photopolymerizable group at the terminal, diamines represented by the formulae (R1) to (R5), and diamines represented by the formulae (z-1) to (z-18) may be used in the production of polyamic acids (A) and (B).

Among the other diamines, p-phenylenediamine, 3, 5-diaminobenzoic acid, 4 '-diaminodiphenylmethane, 4' -diaminobenzophenone, 2 '-dimethyl-4, 4' -diaminobiphenyl, 2- (2, 4-diaminophenoxy) ethyl methacrylate, 2, 4-diamino-N, N-diallylaniline, diamines of the formulae (R1) to (R5), diamines of the formulae (z-1) to (z-18), diamines of the formulae (Dp-1) to (Dp-3), and diamines of the formulae (Ox-1) to (Ox-2) are preferable from the viewpoint of preferably obtaining the effects of the present invention.

In the case of producing the polyamic acid (a), the amount of the other diamine used is preferably 1 to 99 mol%, more preferably 1 to 95 mol%, and still more preferably 5 to 95 mol% based on the total diamine components used. In the case of producing the polyamic acid (B), the amount of the other diamine used is preferably 1 to 99 mol%, more preferably 2 to 99 mol%, and still more preferably 2 to 98 mol% based on the total diamine components used.

In the case of producing the polyamic acids (a) and (B), at least one of the diamines represented by the following formula (5) can be used in order to improve the solubility of the polymer in the liquid crystal aligning agent in a solvent and to improve the voltage holding ratio of the liquid crystal alignment film to be obtained.

H₂N-Y₁-NH₂ (5)

Wherein, Y₁Represents a divalent organic group having a structure represented by the following formula (6).

In the formula (6), D represents a protecting group which is released by heating and substituted with a hydrogen atom, and represents a bonding site with another structure. A preferred structure of D is tert-butoxycarbonyl.

Preferred specific examples of the diamine represented by the formula (5) are shown below. In the following, Boc represents a tert-butoxycarbonyl group.

When the diamine represented by the formula (5) is used, the amount of the diamine represented by the formula (5) is preferably 1 to 50 mol%, more preferably 5 to 40 mol%, based on the total amount of the diamine components used, in the case of producing either of the polyamic acids (a) and (B).

(Tetracarboxylic acid component)

In the case of producing the polyamic acids (a) and (B), the tetracarboxylic acid component to be reacted with the diamines (a) and (B) may be not only a tetracarboxylic dianhydride but also a derivative of a tetracarboxylic dianhydride such as a tetracarboxylic acid, a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester, or a tetracarboxylic acid dialkyl ester dihalide.

Examples of the tetracarboxylic dianhydride or derivative thereof include: aromatic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, or derivatives thereof. Here, the aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group of an aromatic ring. The aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. Among them, it is not necessary to be composed of only a chain hydrocarbon structure, and a part thereof may have an alicyclic structure or an aromatic ring structure. The alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an alicyclic structure. Wherein none of these four carboxyl groups is bonded to an aromatic ring. Further, the alicyclic structure need not be solely composed, and a part thereof may have a chain hydrocarbon structure or an aromatic ring structure. Among the above tetracarboxylic dianhydrides or derivatives thereof, the tetracarboxylic dianhydrides represented by the following formula (3) or derivatives thereof are preferred.

Wherein, in the formula (3), X represents a structure selected from the group consisting of the following (X-1) to (X-13).

In the above formula (x-1), R¹～R⁴Each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom or a phenyl group. R⁵And R⁶Each independently represents a hydrogen atom or a methyl group. j and k are each independently 0 or 1, A₁And A₂Each independently represents a single bond, ether (-O-), carbonyl (-CO-), ester (-COO-), phenylene (-O-), sulfonyl (-SO-), or the like₂-) or an amide (-CONH-), two A' s₂Optionally the same or different. The bond A1 is a bond to one acid anhydride group, and the bond A2 is a bond to the other acid anhydride group.

Preferable specific examples of the above formulae (x-12) and (x-13) include the following formulae (x-14) to (x-29). Denotes a bond.

As a preferred example of the tetracarboxylic dianhydride represented by the above formula (3) or a derivative thereof, a tetracarboxylic dianhydride represented by the above formula (3) wherein X is represented by the above formulae (X-1) to (X-7), (X-11) to (X-13) or a derivative thereof can be mentioned.

The use ratio of the tetracarboxylic dianhydride represented by the above formula (3) or its derivative is preferably 1 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, based on 1mol of the tetracarboxylic acid component used, in the case of either of the polyamic acids (a) and (B).

The tetracarboxylic acid component used for producing the polyamic acids (a) and (B) may contain a tetracarboxylic dianhydride or a derivative thereof other than the tetracarboxylic acid dianhydride represented by the above formula (3).

The polyamic acids (a) and (B) are produced by (condensation polymerization) reacting a diamine component containing the diamine (a) or the diamine (B) with a tetracarboxylic acid component in a solvent. The solvent is not particularly limited as long as the polymer formed by dissolution is present.

Specific examples of the solvent include: n-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, gamma-butyrolactone, N-dimethylformamide, N-dimethylacetamide, dimethyl sulfoxide, and 1, 3-dimethyl-2-imidazolidinone. When the solubility of the polymer in the solvent is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a solvent represented by the following formulae [ D-1 ] to [ D-3 ] can be used.

(formula [ D-1 ]]In (D)¹Represents an alkyl group having 1 to 3 carbon atoms, formula [ D-2 ]]In (D)²Represents an alkyl group having 1 to 3 carbon atoms, formula [ D-3 ]]In (D)³Represents an alkyl group having 1 to 4 carbon atoms).

These solvents may be used alone or in combination. Further, even if the solvent is a solvent that does not dissolve the polymer, the solvent may be used in combination with the polymer in a range that does not precipitate the polymer to be produced.

When the diamine component and the tetracarboxylic acid component are reacted in a solvent, the reaction may be carried out at any concentration, and the concentration of the diamine component and the tetracarboxylic acid component in the solvent is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction may be carried out at a high concentration at the initial stage of the reaction, and then the solvent may be added.

In the reaction, the ratio of the total mole number of the diamine component to the total mole number of the tetracarboxylic acid component (total mole number of the diamine component/total mole number of the tetracarboxylic acid component) is preferably 0.8 to 1.2. Similarly to the usual polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the specific polymer produced.

The polyamic acid ester as a polyimide precursor can be obtained, for example, by the following known methods: [I] a method of reacting a polyamic acid obtained by the above synthesis reaction with an esterifying agent, [ II ] a method of reacting a tetracarboxylic acid diester with a diamine, [ III ] a method of reacting a tetracarboxylic acid diester dihalide with a diamine, and the like.

[ polyimide ]

The polyimide contained in the liquid crystal aligning agent of the present invention is the polyimide (a) or (B) obtained by ring closure of the polyimide precursor. In the polyimide, the ring-closure ratio of the amic acid group (also referred to as imidization ratio) does not necessarily need to be 100%, and can be arbitrarily adjusted.

Examples of the method for obtaining the polyimides (a) and (B) by imidizing a polyimide precursor include: thermal imidization by directly heating a solution of a polyimide precursor, or catalytic imidization by adding a catalyst to a solution of a polyimide precursor. The temperature for thermal imidization of the polyimide precursor in the solution is preferably 100 to 400 ℃, more preferably 120 to 250 ℃, and is preferably carried out while removing water produced by the imidization reaction from the system.

The catalyst imidization of the polyimide precursor is carried out by: a basic catalyst and an acid anhydride are added to a solution of a polyimide precursor, and the mixture is stirred at-20 to 250 ℃, preferably 0 to 180 ℃. The amount of the basic catalyst is 0.5 to 30 times, preferably 2 to 20 times, the amount of the basic catalyst is 1 to 50 times, preferably 3 to 30 times, the amount of the acid anhydride is 1 to 50 times, preferably 3 to 30 times, the amount of the acid amide group. Examples of the basic catalyst include: pyridine, triethylamine, trimethylamine, tributylamine trioctylamine, and the like, and among them, pyridine is preferable because it has an appropriate basic property for allowing the reaction to proceed. Examples of the acid anhydride include: acetic anhydride, trimellitic anhydride, pyromellitic anhydride (pyroracemic anhydride), and the like, among them, acetic anhydride is preferable because purification after completion of the reaction becomes easy when acetic anhydride is used. The imidization rate based on the catalyst imidization can be controlled by adjusting the amount of the catalyst and the reaction temperature, reaction time.

When the polyimide to be produced is recovered from the reaction solution for imidization of the polyimide precursor, the reaction solution may be introduced into a solvent to precipitate the polyimide. As the solvent for precipitation, there may be mentioned: methanol, ethanol, isopropanol, acetone, hexane, butyl cellulose, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, water, and the like. The polymer precipitated by the solvent may be recovered by filtration, and then dried at normal temperature or under reduced pressure or under heating. Further, when the polymer subjected to the precipitation recovery is redissolved in a solvent and the operation of the reprecipitation recovery is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the solvent in this case include alcohols and ketones, and the use of three or more solvents selected from these is preferable because the purification efficiency is further improved.

The polyimide precursor and the polyimide preferably have a weight average molecular weight (Mw) of 1000 to 500000, more preferably 2000 to 300000, in terms of polystyrene as measured by Gel Permeation Chromatography (GPC). The molecular weight distribution (Mw/Mn) represented by the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 15 or less, and more preferably 10 or less. Within this molecular weight range, good alignment properties of the liquid crystal display element can be ensured.

(liquid Crystal alignment agent)

The liquid crystal aligning agent of the present invention is a liquid composition in which the polymer (a), the polymer (B), and other components used as needed are preferably dispersed or dissolved in an appropriate solvent.

The mass ratio ((A)/(B)) of the content of the component (A) to the content of the component (B) in the polymer (A) and the polymer (B) contained in the liquid crystal aligning agent of the present invention is preferably 5/95 to 80/20, and more preferably 10/90 to 60/40. Thus, a liquid crystal alignment film having a higher light transmittance can be provided while maintaining the surface characteristics such as liquid crystal alignment properties required for the liquid crystal alignment film.

The liquid crystal aligning agent of the present invention may contain other polymers (hereinafter, also referred to as other polymers) in addition to the polymers (a) and (B) for the purpose of improving, for example, electrical characteristics and solution characteristics.

The main skeleton of the other polymer is not particularly limited, and examples thereof include: a main skeleton such as a polyimide precursor, polyimide, polysiloxane, polyester, polyamide, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, or poly (meth) acrylate. Among these, at least one selected from the group consisting of polyimide precursors, polyimides, polyamides, polyorganosiloxanes, poly (meth) acrylates, and polyesters is preferable, and at least one selected from the group consisting of polyimide precursors, polyimides, and polysiloxanes is more preferable. Two or more of the other polymers may be used in combination.

The liquid crystal aligning agent of the present invention may contain other components than those described above as necessary. Examples of the component include: a compound selected from at least one of the group consisting of a crosslinkable compound having a substituent selected from at least one of an epoxy group, an isocyanate group, an oxetanyl group, a cyclic carbonate group, a blocked isocyanate group, a hydroxyl group and an alkoxy group, and a crosslinkable compound having a polymerizable unsaturated group, a functional silane compound, a metal chelate compound, a curing accelerator, a surfactant, an antioxidant, a sensitizer, an antiseptic, a compound for adjusting the dielectric constant and the electric resistance of the liquid crystal alignment film. Specific examples of preferable crosslinkable compounds include compounds represented by the following formulas (CL-1) to (CL-11). Examples of the compound for adjusting the dielectric constant and the electric resistance of the liquid crystal alignment film include monoamines having nitrogen-containing aromatic heterocycles, such as 3-aminomethylpyridine.

Examples of the organic solvent used in the liquid crystal aligning agent of the present invention include: n-methyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, N- (N-propyl) -2-pyrrolidone, N-isopropyl-2-pyrrolidone, N- (N-butyl) -2-pyrrolidone, N- (tert-butyl) -2-pyrrolidone, N- (N-pentyl) -2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide, γ -butyrolactone, γ -butyrolactam, N-dimethylformamide, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, Butyl lactate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, diisobutyl methanol (2, 6-dimethyl-4-heptanol), diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisoamyl ether, isopropyl ether, butyl acetate, butyl cellosolve, butyl glycol monobutyl ether, butyl glycol monobutyl ether acetate, butyl ether, butyl glycol monobutyl ether, butyl glycol ether, butyl glycol ether, butyl glycol, butyl ether, butyl, Ethylene carbonate, propylene carbonate, and the like. Two or more of these may be used in combination.

The concentration of the solid component in the liquid crystal aligning agent (the ratio of the total mass of the components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, and the like, and is preferably 1 to 10 mass%. The content is preferably 1% by mass or more in terms of forming a uniform and defect-free coating film, and is preferably 10% by mass or less, particularly preferably 2 to 8% by mass in terms of storage stability of the solution.

< liquid Crystal alignment film >

The liquid crystal alignment film for vertical alignment using the liquid crystal aligning agent of the present invention can be produced by: the liquid crystal aligning agent is applied to a substrate, and the steps of drying and firing are sequentially performed, and if necessary, rubbing treatment, alignment treatment by light irradiation, and the like are performed.

The substrate used in this case is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like may be used. From the viewpoint of process simplification, a substrate on which an ITO electrode or the like for liquid crystal driving is formed is preferably used. In the reflective liquid crystal display element, an opaque substrate such as a silicon wafer may be used as a single-sided substrate, and a material that reflects light such as aluminum may be used as an electrode in this case.

Examples of the method for applying the liquid crystal aligning agent include: screen printing, offset printing, flexographic printing, ink jet method, dipping method, roll coater method, slit coating method, spin coating method, spray coating method, etc., from the viewpoint of improving the production efficiency of the liquid crystal alignment film, a method of coating by flexographic printing or ink jet method is preferred.

After the liquid crystal aligning agent is coated on the substrate, the substrate is dried at preferably 40 to 150 ℃ depending on the solvent used in the liquid crystal aligning agent by a heating means such as a hot plate or a thermal cycle oven IR (infrared ray) type oven, and then fired at preferably 150 to 300 ℃, more preferably 180 to 250 ℃ to form liquid crystal alignment.

The thickness of the liquid crystal alignment film after firing is preferably 5 to 300nm, more preferably 10 to 100nm, because it is disadvantageous in terms of power consumption of the liquid crystal display device if it is too thick, and because reliability of the liquid crystal display device may be lowered if it is too thin.

< liquid crystal display element >

The liquid crystal display element of the present invention includes the liquid crystal alignment film.

When the display mode of the produced liquid crystal display element is VA type, the coating film formed as described above may be used as it is as a liquid crystal alignment film, or may be subjected to a brushing treatment or PSA treatment described later as necessary. On the other hand, when the display mode of the manufactured liquid crystal display element is a vertical electric field type other than the VA type and a horizontal electric field type, the alignment treatment is performed by performing a brushing treatment or a treatment such as polarized ultraviolet irradiation on the formed coating surface.

The liquid crystal aligning agent of the present invention is also preferably used for a liquid crystal display element produced through the following steps: a liquid crystal layer is provided between a pair of substrates having electrodes, a liquid crystal composition containing a polymerizable compound that is polymerized by at least one of active energy rays and heat is disposed between the pair of substrates, and the polymerizable compound is polymerized by at least one of irradiation with the active energy rays and heating while applying a voltage between the electrodes. The applied voltage may be, for example, 5 to 50V DC or AC. In addition, as the active energy ray, ultraviolet rays are preferable. The ultraviolet ray is an ultraviolet ray containing light having a wavelength of 300 to 400nm, and preferably an ultraviolet ray containing light having a wavelength of 310 to 360 nm. The dose of light irradiation is preferably 0.1 to 20J/cm²More preferably 1 to 20J/cm²。

Examples of the method for producing a liquid crystal display element using the liquid crystal aligning agent of the present invention include the following methods: the liquid crystal aligning agent is applied to a pair of substrates having conductive films to form a coating film, the coating films are arranged to face each other with a layer of liquid crystal molecules interposed therebetween to form a liquid crystal cell, and the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates.

The liquid crystal display device controls the pretilt angle of the liquid crystal molecules by a psa (polymer sustained alignment) method. In the PSA method, a small amount of a photopolymerizable compound, for example, a photopolymerizable monomer, is mixed into a liquid crystal material in advance, a liquid crystal cell is assembled, and then the photopolymerizable compound is irradiated with ultraviolet light or the like while a predetermined voltage is applied to the liquid crystal layer, whereby the pretilt angle of liquid crystal molecules is controlled by the resulting polymer. Since the alignment state of the liquid crystal molecules when the polymer is produced is also stored after the voltage is removed, the pretilt angle of the liquid crystal molecules can be adjusted by controlling an electric field or the like formed in the liquid crystal layer. In addition, since the PSA method does not require a rubbing process, it is suitable for forming a vertical alignment type liquid crystal layer in which it is difficult to control the pretilt angle by the rubbing process.

In the liquid crystal display device of the present invention, a substrate with a liquid crystal alignment film is obtained from the liquid crystal alignment agent of the present invention by the above-described method, and then a liquid crystal cell is produced by a known method to produce a liquid crystal display device.

Examples of a method for manufacturing a liquid crystal cell include: a method of preparing a pair of substrates on which liquid crystal alignment films are formed, spreading spacers on the liquid crystal alignment film of one substrate, bonding the other substrate with the liquid crystal alignment film surface facing inward, and injecting liquid crystal under reduced pressure to seal the substrates; and a method of dropping a liquid crystal on the liquid crystal alignment film surface on which the spacers are dispersed, and then bonding the substrates to each other to seal the substrates.

The liquid crystal may be mixed with a polymerizable compound that is polymerized by ultraviolet irradiation or heat as described above. Examples of the polymerizable compound include compounds having one or more polymerizable unsaturated groups such as an acrylate group and a methacrylate group in the molecule, and examples of the polymerizable compound include polymerizable compounds represented by the following formulas (M-1) to (M-3).

In this case, the content of the polymerizable compound is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the liquid crystal component. If the amount of the polymerizable compound is less than 0.01 parts by mass, the polymerizable compound is not polymerized, and alignment control of the liquid crystal cannot be performed, and if the amount of the polymerizable compound is more than 10 parts by mass, the amount of unreacted polymerizable compound increases, and the image sticking characteristics of the liquid crystal display element deteriorate. After the liquid crystal cell is produced, the polymerizable compound is polymerized by heat or ultraviolet irradiation while applying an ac/dc voltage to the liquid crystal cell. Thereby, the alignment of the liquid crystal molecules can be controlled.

The liquid crystal aligning agent of the present invention can be used for a liquid crystal display element manufactured through the following steps, that is, can be used in an SC-PVA mode: a liquid crystal layer is provided between a pair of substrates having electrodes, a liquid crystal alignment film containing polymerizable groups that are polymerized by at least one of active energy rays and heat is disposed between the pair of substrates, and a voltage is applied between the electrodes. Here, as the active energy ray, ultraviolet rays are preferable. The ultraviolet rays used in the PSA system are preferably applied. When the polymerization is carried out by heating, the heating temperature is 40 to 120 ℃, preferably 60 to 80 ℃. Further, ultraviolet rays and heating may be performed simultaneously.

In order to obtain a liquid crystal alignment film containing a polymerizable group that is polymerized by at least one of active energy rays and heat, examples of the liquid crystal alignment film include: a method of adding a compound containing the polymerizable group to a liquid crystal aligning agent, and a method of using a polymer component containing the polymerizable group. As a specific example of the polymer having a polymerizable group, a polymer obtained using a diamine having a function of polymerizing by the above-mentioned light irradiation can be cited.

Examples

The present invention will be described in more detail with reference to the following examples, but the present invention is not to be construed as being limited to these examples.

The following abbreviations for the compounds, methods for measuring the respective properties, methods for preparing measurement samples and the like used for the measurement, and the like are as follows. Unless otherwise specified, numerical values and numerical value ratios are used as quality references.

< diamine (a) >

< diamine (b) >

< other diamines >

(Boc represents a tert-butoxycarbonyl group.)

(tetracarboxylic dianhydride)

(organic solvent)

NMP: n-methyl-2-pyrrolidone, BCS: butyl cellosolve.

THF: tetrahydrofuran.

[ viscosity ]

The viscosity of the polyamic acid solution or the like was measured at 25 ℃ using an E-type viscometer TVE-22H (manufactured by Toyobo industries Co., Ltd.) with a sample volume of 1.1mL (mL) and a cone rotor TE-1 (1 ℃ C., 34', R24).

[ measurement of molecular weight ]

The molecular weights of the polyimide precursor, polyimide, and the like were measured as follows using a gel permeation chromatography at room temperature (GPC) apparatus (GPC-101) (manufactured by Showa Denko K.K.) and a column (KD-803, KD-805) (manufactured by Shodex K.K.).

Temperature of the column: at 50 ℃.

Eluent: n, N-dimethylformamide (as additive, lithium bromide monohydrate (LiBr. H)₂O)30mmol/L (liter), phosphoric acid/anhydrous crystals (O-phosphoric acid) 30mmol/L, Tetrahydrofuran (THF) 10 ml/L).

Flow rate: 1.0 ml/min.

Calibration curve preparation standard sample: TSK-standard polyethylene oxides (molecular weight: about 900000, 150000, 100000 and 30000, manufactured by Tosoh corporation) and polyethylene glycols (molecular weight: about 12000, 4000 and 1000, manufactured by Polymer Laboratory corporation).

[ measurement of imidization ratio ]

To an NMR (nuclear magnetic resonance) sample tube (. phi.5 (manufactured by Softweed scientific Co.)) was added polyimide powder (20mg), and deuterated dimethyl sulfoxide (DMSO-d 6, 0.05 mass% TMS (tetramethylsilane) mixture) (0.53ml) was added, followed by completely dissolving the mixture with ultrasonic waves. The solution was subjected to proton NMR measurement at 500MHz in an NMR spectrometer (JNW-ECA 500) (manufactured by electronic DATUM, Japan). The imidization ratio was determined as follows: the proton derived from a structure which does not change before and after imidization is determined as a reference proton, and the peak integral value of the proton derived from an amic acid-derived NH group appearing in the vicinity of 9.5 to 10.0ppm are used to obtain the proton from the following formula.

Imidization ratio (%) - (1-. alpha.x/y). times.100

In the above formula, x is a peak integral value of a proton derived from an NH group of amic acid, y is a peak integral value of a reference proton, and α is a ratio of the number of reference protons to the number of protons of one NH group of amic acid in the case of polyamic acid (imidization ratio of 0%).

< Synthesis of diamine DA-v-7 >

Compound [ DA-v-7 ] was synthesized according to the following scheme. "MeO" represents methoxy.

(Synthesis of Compound 3(3a, 3b mixture))

Magnesium (15.39g, 63.3mmol, 1.5eq.) was added to a four-necked flask, vacuum-dried for 1 hour in a vacuum pump, and then THF (100g) was added thereto via a syringe and stirred at room temperature. Next, a solution of Compound 1(100g, 42.2mmol) in THF (300g) was slowly added dropwise at a rate of about constant reflux. Then, the reaction solution was cooled to 0 ℃, and a solution of compound 2(105.60g, 42.2mmol, 1.0eq.) in THF (200g) was added dropwise. After completion of the dropwise addition, the temperature of the reaction solution was returned to room temperature, and stirring was carried out at room temperature for 3 hours. Then, toluene (1L) was added to dilute the reaction solution, and the reaction solution was cooled to 0 ℃ again, and a 10% acetic acid solution (500g) was slowly added dropwise.

Subsequently, the aqueous layer was removed by a liquid separation operation, and the organic layer was washed with saturated saline (1L), saturated aqueous sodium bicarbonate (1L), and saturated saline (1L), respectively, and dried over anhydrous magnesium sulfate. Then, the mixture was filtered and distilled off by an evaporator to obtain crude crystals (172g) of Compound 3. The obtained crude crystals were used directly in the following reaction.

(Synthesis of Compound 4)

The crude crystals of compound 3 (172g, 422mmol) were reacted with a mixture of p-toluenesulfonic acid monohydrate (4.82g, 25.3mmol, 0.06eq.) in dehydrated toluene (MS4A dehydrate, 2L) at reflux for 2 hours with removal of water. After completion of the reaction, about half of the amount of toluene used was distilled off in an evaporator, and then the solution was stirred at room temperature to precipitate a solid. The obtained solid was filtered to obtain crystals of Compound 4 (yield 150g, yield 91%).

(Synthesis of Compound 5(5a, 5b mixture))

A mixture of compound 4(108g, 276mmol), 5% palladium on carbon (aqueous, 11g, 10 wt%), ethyl acetate (1L), and ethanol (1L) was stirred at room temperature in the presence of hydrogen. After completion of the reaction, toluene (2L) was added to dissolve the crystals, and then the reaction mixture was filtered through celite (celite), and the celite was washed with 1L of toluene. The filtrate was concentrated under reduced pressure, whereby the objective compound 5 (yield 103.3g, yield 95%) was obtained.

(Synthesis of Compound 6)

To a solution of Compound 5(95.4g, 243mmol) in dichloromethane (800mL) was added BBr dropwise at 0 ℃ under nitrogen substitution₃(1.0M－CH₂Cl₂243mL, 1.01 mol). After the dropwise addition, the mixture was stirred at 0 ℃ for 2 hours. After the reaction, the reaction solution was added to distilled water in small amounts. The extract was extracted with ethyl acetate (1L), and the extract was washed twice with 500mL of distilled water. After the organic layer was dried over magnesium sulfate, the solvent was distilled off under reduced pressure. The obtained crude product was recrystallized from ethanol, filtered, and washed with ethanol, whereby the objective compound 6 (yield 18.6g, yield) was obtained21％)。

(Synthesis of Compound 8)

To a mixture of compound 6(10.0g, 26.4mmol), potassium carbonate (11.0g, 79.2mmol, 3eq.) and toluene (50g) was added dropwise a solution of compound 7(5.35g, 26.4mmol) in toluene (20g) under reflux. After the addition, stir at reflux-evening-out. After completion of the reaction, the reaction mixture was cooled to about 60 ℃ and then ethyl acetate (500g) was added thereto, followed by washing with distilled water three times. The organic layer was dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The obtained crude product was recrystallized from an acetonitrile/ethanol (2: 1) solution, and after filtration, the filtered crystals were washed with ethanol to obtain crude crystals of Compound 8. By column chromatography (SiO)₂，CHCl₃) This crude crystal was purified to obtain a crystal of Compound 8 (yield 7.1g, yield 49%).

(Synthesis of DA-v-7)

A mixture of compound 8(12.2g, 22.4mmol), 5% palladium on carbon (aqueous, 1.22g, 10 wt%), dioxane (120g) was stirred in the presence of hydrogen at 60 ℃ for 4 hours. After completion of the reaction, nitrogen substitution was performed, and then filtration was performed with celite while maintaining the temperature at 60 ℃. The solvent was distilled off from the filtrate under reduced pressure, and as a result, a crude product was obtained. This crude product was recrystallized from 2-propanol/ethyl acetate (2: 1), whereby DA-v-7 (yield 8.0g, yield 74%) as the objective compound was obtained.

¹H－NMR(500MHz，CDCl₃)：δ(ppm)＝7.725(1H，d)，7.577(2H，m)，7.272(2H，m)，7.102(1H，s)，6.791(1H，d)，6.207(1H，d)，6.117(1H，dd)，3.621(4H，broad)，2.553(1H，m)，2.067－0.863(31H，m)。

< Synthesis of diamine [ DA-n-10 ]

The compound [ DA-n-10 ] was synthesized according to the following scheme.

(Synthesis of Compound [1]

To tert-butyl (5-hydroxy-1-naphthyl) carbamate (27.0g, 104mmol) were charged N, N-dimethylformamide (216g) and potassium carbonate (33g, 239mmol), and stirred at 80 ℃. Subsequently, a solution of 1, 2-bis (4-methylbenzenesulfonate) -1, 2-ethanediol (18.0g, 496mmol) in N, N-dimethylformamide (162g) was added dropwise via a dropping funnel, and the mixture was stirred at 80 ℃ overnight. After completion of the reaction, the reaction mixture was poured into water (2268g) to precipitate crystals. The mixture was filtered using a buchner funnel to give a dark purple crystal (93g) with stickiness. To the obtained crude product was added N, N-dimethylformamide, and the mixture was dissolved by heating at 80 ℃ and crystallized from methanol while cooling to room temperature, followed by filtration and drying to obtain Compound [1] (yield: 28.0g, 51.4mmol, yield 67%).

¹H－NMR(500MHz，DMSO－d₆)：δ(ppm)＝9.14(s，2H)，7.98(d，J＝10.0Hz，2H)，7.64(d，J＝10.0Hz，2H)，7.55(d，J＝10.0Hz，2H)，7.46(t，J＝7.5Hz，2H)，7.39(t，J＝7.5Hz，2H)，7.13(d，J＝10.0Hz，2H)，4.65(s，4H)，1.49(s，18H)。

(Synthesis of Compound [ DA-n-10 ]

To compound [1] (28.0g, 51.4mmol) were charged chloroform (374g) and potassium carbonate (33g, 239mmol), and stirred at 80 ℃. Then, trifluoroacetic acid (31.0g, 313mmol) was slowly dropped through a dropping funnel, and the mixture was heated and stirred at 50 ℃ for 6 hours, whereby gray crystals were precipitated in the reaction system. After cooling to 25 ℃, the reaction mixture was poured into water (374g) and filtered. To the obtained crystals were added triethylamine and water and stirred to release diamine from trifluoroacetate, followed by filtration, washing with methanol and then hexane and drying to obtain compound [ DA-n-10 ] (yield: 9.30g, 27.0mmol, yield 86%).

¹H－NMR(500MHz，DMSO－d₆)：δ(ppm)＝7.65(d，J＝7.5Hz，2H)，7.41(d，J＝8.0Hz，2H)，7.29(t，J＝8.0Hz，2H)，7.12(t，J＝8.0Hz，2H)，7.00(t，J＝7.5Hz，2H)，6.67(d，J＝7.5Hz，2H)，5.62(s，4H)，4.56(s，4H)。

[ Synthesis of Polyamic acid ]

< Synthesis example 1 >

DA-4 (1.66g, 7.00mmol), DA-5 (2.89g, 8.75mmol), DA-v-6 (5.30g, 7.00mmol) and DA-13 (2.43g, 12.3mmol) were weighed out in a 100mL four-necked flask equipped with a stirrer, and NMP (49.1g) was added and dissolved by stirring. While this diamine solution was stirred, DC-3 (7.53g, 33.6mmol) was added, NMP (30.1g) was further added, and the mixture was stirred at 60 ℃ for 15 hours to obtain a solution of polyamic acid (A-a-1, viscosity: 649 mPas, Mn: 14231).

< Synthesis examples 2 to 7 >

Synthesis example 1 was repeated in the same manner with the exception that the diamine component and the acid dianhydride component were changed to those shown in Table 1, thereby obtaining polymer (polyamic acid) solutions (A-a-2), (A-a-3), (A-b-4), (A-b-5), (A-r-6), and (A-r-7) shown in Table 1.

The viscosities and molecular weights of the polyamic acids obtained in synthesis examples 1 to 7 are shown in table 1 below.

[ Table 1]

[ preparation of liquid Crystal Aligning agent ]

< comparative example 1 >

NMP (6.0g) and BCS (8.0g) were added to the solution (6.0g) of polyamic acid (A-a-1) obtained above, and the mixture was stirred at room temperature for 10 hours to prepare a liquid crystal alignment agent (R-1) containing 6 mass% of polyamic acid (A-a-1), 54 mass% of NMP, and 40 mass% of BCS.

< comparative examples 2 and 3 >

Liquid crystal alignment agents (R-2) and (R-3) shown in Table 2 were obtained in the same manner as in comparative example 1 except that the polyamic acids (A-a-2) and (A-a-3) were changed to polyamic acids (A-a-2) and (A-a-3), respectively.

< example 1 >

Using the polyamic acid (a-1) and the polyamic acid (a-b-4) prepared in the above manner, instead of the polyamic acid (a-1), as shown in table 2 below, a liquid crystal aligning agent (1) was obtained in which the component ratio (solid content-equivalent mass ratio) of the polyamic acid (a-1) to the polyamic acid (a-b-4) was (a-1)/(a-b-4) 30/70, and the component mass ratio of the solid content of the polymer component to the solvent was (solid content)/NMP/BCS 6/54/40.

< examples 2 to 4, comparative examples 4 to 9 >

Liquid crystal alignment agents (2) to (4) of examples 2 to 4 shown in Table 2 below and liquid crystal alignment agents (R-4) to (R-9) of comparative examples 4 to 9 were obtained in the same manner as in example 1 except that the polyamic acid solution was changed to those shown in Table 2 below.

In table 2, the numerical values in parentheses in the polymer composition represent the blending ratio (parts by mass) of each polymer component with respect to 100 parts by mass of the total of the polymer components used in the preparation of the liquid crystal aligning agent. The solid content ratio and the solvent composition ratio indicate the blending ratio (parts by mass) of the polymer solid content and each organic solvent to 100 parts by mass of the total amount of the polymer solid content and each organic solvent used for the production of the liquid crystal aligning agent.

[ Table 2]

[ production of liquid Crystal alignment film ]

Using the liquid crystal aligning agents prepared in the above examples, liquid crystal alignment films were produced as follows.

The liquid crystal aligning agents prepared in the above examples were spin-coated on a quartz substrate or a silicon wafer, dried on a hot plate at 70 ℃ for 90 seconds, and then fired in a hot air circulation oven (MB 1-1G 3030X, manufactured by Denko) at 230 ℃ for 20 minutes to form a liquid crystal alignment film having a film thickness of 100 nm.

[ measurement of refractive index of liquid Crystal alignment film ]

The refractive index at 250-800 nm was measured by fitting using a CAUCHY model using a Spectroscopic ellipsometer (manufactured by J.A. Woollam Co.) (M-2000). The results are shown in Table 3. The refractive index at 550nm is reported in Table 3. The refractive index is "good" when it is greater than 1.62, and "poor" when it is 1.62 or less.

[ measurement of transmittance of liquid Crystal alignment film ]

The transmittance at 380 to 800nm was measured using an ultraviolet-visible spectrophotometer (manufactured by Shimadzu corporation) (UV-2600). The results are shown in Table 3. The average value of the transmittance at 380 to 800nm is shown in Table 3.

The measuring cell was produced using two quartz substrates. A liquid crystal alignment film was formed on one of the two sheets, and a quartz substrate on which the liquid crystal alignment film was not formed was bonded with the surface on which the liquid crystal alignment film was formed as the inner side. A refractant liquid (contact liquid, manufactured by Shimadzu instruments) was inserted between the two wells with a pipette to prepare a measurement cassette. The refractive liquid is used from 11 kinds of 0.01 scale of 1.60 to 1.70 according to the respective refractive indexes.

The transmittance of more than 99.0% was evaluated as "good", and the transmittance of 99.0% or less was evaluated as "poor".

[ Table 3]

The entire contents of the specification, claims and abstract of japanese patent application No. 2019-173298 filed 24.9.9.2019 are incorporated herein by reference as disclosure of the specification of the present invention.

Claims

1. A liquid crystal aligning agent comprising the following components (A) and (B),

(A) the components: at least one polymer (A) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (a) having at least one selected from the group consisting of structures represented by the following formulae (S1) to (S3), and a polyimide which is an imide product of the polyimide precursor,

(B) the components: at least one polymer (B) selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine (B) represented by the following formula (2) and a polyimide which is an imide compound of the polyimide precursor,

X¹and X²Each independently represents a single bond, - (CH)₂)_a－、－CONH－、－NHCO－、－CON(CH₃) -, -NH-, -O-, -COO-, -OCO-or- ((CH)₂)_a1－A₁)_m1-, said- (CH)₂)_aIn the formula, a is an integer of 1 to 15, and the- ((CH)₂)_a1－A₁)_m1In the formula, a1 is an integer of 1 to 15, A₁Represents an oxygen atom or-COO-, m₁Is an integer of 1 to 2; at m₁In the case of 2, a plurality of a1 and A₁Each independently has the definition; g¹And G²Each independently represents a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms and a divalent alicyclic group having 3 to 8 carbon atoms; any hydrogen atom on the cyclic group is optionally substituted by an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms or a fluorine atom; m and n are respectively and independently integers of 0-3, and m + n is 1-6; r¹Represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms to form R¹Optionally substituted with fluorine atoms,

-X³-R² (S2)

X³represents a single bond, -CONH-, -NHCO-, -CON (CH)₃)－、－NH－、－O－、－CH₂O－、－COO-or-OCO-; r²Represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms to form R²Optionally substituted with fluorine atoms,

-X⁴-R³ (S3)

X⁴represents-CONH-, -NHCO-, -O-, -CH₂O－、－OCH₂-, -COO-or-OCO-; r³It is represented as a structure having a steroid skeleton,

A₁and A₂Each independently represents a divalent monocyclic group or condensed ring group optionally having a substituent, A₁And A₂At least one of (a) represents a divalent condensed ring group optionally having a substituent; l represents a single bond, -COO-, -CO-S-, -CO-, -CONR-, -O-, -S-or a divalent organic group, wherein in the-CONR-, R represents a hydrogen atom or a monovalent alkyl group having 1-6 carbon atoms; m and n are each independently integers of 1 to 3.

2. The liquid crystal aligning agent according to claim 1,

in the formula (2), the condensed ring group is a divalent group obtained by removing two hydrogen atoms from a condensed ring of any one of naphthalene, anthracene, pyrene, indole, carbazole, coumarin, benzopyrone, quinoline, and isoquinoline.

3. The liquid crystal aligning agent according to claim 1 or 2,

the diamine (a) is a diamine represented by the following formula [1] or formula [2],

x represents a single bond, -O-, -C(CH₃)₂－、－NH－、－CO－、－(CH₂)_m－、－SO₂－、－O－(CH₂)_m－O－、－O－C(CH₃)_m－、－CO－(CH₂)_m－、－NH－(CH₂)_m－、－SO₂－(CH₂)_m－、－CONH－(CH₂)_m－、－CONH－(CH₂)_m－NHCO－、－COO－(CH₂)_m－OCO－、－COO－、－CONH－、－NH－(CH₂)_m-NH-or-SO₂－(CH₂)_m－SO₂-; m is an integer of 1-8; y represents the formula [ S1]]～[S3]Is any of the structures of (1), formula [2]]Optionally the two Y's in (a) are the same or different.

4. The liquid crystal aligning agent according to claim 3,

the diamine represented by the formula [1] is represented by the following formulae [ S-1 ] to [ S-18 ],

n is an integer of 1 to 20,

5. the liquid crystal aligning agent according to claim 3,

the diamine represented by the formula [2] is represented by the following formulae [ W-1 ] to [ W-6 ],

X^p1～X^p8are each independently- (CH)₂)_a－、－CONH－、－NHCO－、－CON(CH₃)－、－NH－、－O－、－CH₂O－、－CH₂OCO-, -COO-, or-OCO-, the- (CH)₂)_aIn the formula, a is an integer of 1 to 15; x^s1～X^s4Each independently represents-O-, -CH₂O－、－OCH₂-, -COO-or-OCO-; x_a～X_frepresents-O-, -NH-, -O- (CH)₂)_m－O－、－C(CH₃)₂－、－CO－、－COO－、－CONH－、－(CH₂)_m－、－SO₂－、－O－C(CH₃)₂－、－CO－(CH₂)_m－、－NH－(CH₂)_m－、－NH－(CH₂)_m－NH－、－SO₂－(CH₂)_m－、－SO₂－(CH₂)_m－SO₂－、－CONH－(CH₂)_m－、－CONH－(CH₂)_m-NHCO-, or-COO- (CH)₂)_m－OCO－；R^1a～R^1hEach independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms; m is an integer of 1 to 8.

6. The liquid crystal aligning agent according to any one of claims 1 to 5,

a of the formula (2)₁、A₂The monocyclic group in (1) is a divalent group obtained by removing two hydrogen atoms from a monocyclic ring of any one of benzene and pyridine.

7. The liquid crystal aligning agent according to any one of claims 1 to 6,

l in the formula (2) is a single bond; - (CH)₂)_n-, where n is an integer of 1 to 20; -O- (CH)₂)_n-O-, wherein n is an integer from 1 to 20; -O- (CH)₂)_n-, where n is an integer of 1 to 20; -S- (CH)₂)_n-S-, wherein n is an integer of 1 to 20; or-S- (CH)₂)_n-, where n is an integer of 1 to 20.

8. The liquid crystal aligning agent according to any one of claims 1 to 7,

m and n of the formula (2) are 1 or 2.

9. The liquid crystal aligning agent according to any one of claims 1 to 8,

the polyimide precursor of at least one of the polymer (A) and the polymer (B) is obtained by a polymerization reaction of a diamine component containing the diamine (a) or the diamine (B) and a tetracarboxylic acid component containing a tetracarboxylic dianhydride represented by the following formula (3) or a derivative thereof,

x represents a structure selected from the group consisting of (X-1) to (X-13),

R¹～R⁴each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom or a phenyl group; r⁵And R⁶Each independently represents a hydrogen atom or a methyl group; j and k are each independently an integer of 0 or 1, A₁And A₂Each independently represents a single bond, -O-, -CO-, -COO-, a phenylene group, a sulfonyl group, or an amide group, and two A' s₂Optionally the same or different; the bond A1 is a bond to one acid anhydride group, and the bond A2 is a bond to the other acid anhydride group.

10. The liquid crystal aligning agent according to claim 9,

x in the formula (3) is a structure selected from the group consisting of the formulas (X-1) to (X-7), (X-11) to (X-13).

11. The liquid crystal aligning agent according to any one of claims 1 to 10,

the component (A) is contained so that the mass ratio of the content of the component (A) to the content of the component (B), i.e., (A)/(B), is 5/95-80/20.

12. A liquid crystal alignment film formed by using the liquid crystal aligning agent according to any one of claims 1 to 11.

13. A liquid crystal display element comprising the liquid crystal alignment film according to claim 12.

14. A method for manufacturing a liquid crystal display element comprises the following steps:

a liquid crystal aligning agent according to any one of claims 1 to 11, which is applied to a pair of substrates having conductive films to form a coating film, wherein the coating films are arranged to face each other with a layer of liquid crystal molecules interposed therebetween to form a liquid crystal cell, and wherein the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates.